Problem: $ { \left[\begin{array}{rr}{0} & {2} \\ {4} & {2}\end{array}\right]-\left[\begin{array}{rr}{3} & {-1} \\ {1} & {-1}\end{array}\right] = {?} } $
To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{0}-{3} & {2}-{-1} \\ {4}-{1} & {2}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-3} & {3} \\ {3} & {3}\end{array}\right]}$